Collapsible containers are well known and used in a variety of environments. The collapsible container disclosed herein will be useful in any environment wherein it is desired that a container collapse as product is removed from the container. However, when disclosing aspects of the collapsible container herein, the liquid dispensing arts are focused upon. Notably, in particular embodiments, the present application focuses upon collapsible containers employed in liquid dispensers that most commonly dispense hand-treatment products such as soaps, hand sanitizers, and lotions. Nevertheless, it should again be stressed that the collapsible containers herein can be employed in a multitude of environments because the containers taught herein collapse upon the removal of product, regardless of the particular product therein or the particular environment in which they are employed.
Collapsible containers for liquid dispensers range in complexity from simple film-type plastic bags, such as those in the well-known bag-in-a-box type dispensers (e.g. U.S. Pat. No. 5,598,952), to more rigid yet collapsible structures such as that shown U.S. Pat. No. 5,083,678. The containers are sealed such that the removal of product from the container causes the container volume to decrease by the volume of the product removed. Typically, a pump is sealed to the container, and the actuation of the pump causes product to be removed from the container. In such environments, the collapsing of the container presents a number of advantages.
First, when the available product is dispensed from the container, the container is fully collapsed and thus takes up less space in any rubbish bin and landfill. Second, when the inlet to the pump is positioned within the volume of the container, the collapsing of the container can result in a more efficient evacuation of the container volume, as the collapsing of the container will force product within the container toward the pump inlet. In particular embodiments, such as in U.S. Pat. No. 5,083,678, the collapsing of the container can also serve to urge product in the container toward a sight window in a dispenser housing so that the depletion of the product within the container can be more readily monitored through that sight windows. The use of sight windows in dispenser housings, particularly wall-mounted dispensers for hand-treatment products, is well known. Finally, by providing containers that collapse in a predictable manner, it is possible to ensure that the container does not change shape in such a manner that it bulges, kinks or twists within the dispenser and undesirably contacts the internal structures of the dispenser housing. When containers bulge, kink or twist in this manner they can undesirably place stresses on the structures of the dispenser housing. This can lead to an improper seating of the container in the dispenser and may also cause the elements actuating the pump to work harder, thus increasing the power requirements of the dispenser.
Some prior art provides for more controlled collapsing of containers through the use of fold lines formed in the container walls. Such include U.S. Pat. Nos. 5,445,288 and 5,556,005, wherein fold lines are provided so as to create container that collapses to form an I-beam structure. Regardless of the implementation of the fold lines, these structures still bulge, kink and twist to some extent. Additionally, the bulging, kinking and twisting of the container can draw the container away from the aforementioned sight windows, thus obscuring the view of the level of product left in the container.
Prior art collapsible container are also commonly blow molded or otherwise formed as an completed but empty container, and these empty containers are stored until sales of product make it advisable to fill those empty containers to fill product orders. Thus, large storage space must be devoted to empty containers, and this is undesirable.
While the prior art does provide for different types of collapsible containers, the focus on complicated structures with fold lines and other features for urging product to lie close to a sight window is misplaced. The present invention substantially improves the art by simplifying the collapsible container while improving its functionality, particularly with respect to urging product toward a sight window of a dispenser. Also, the prior art can be improved upon by avoiding the need to store voluminous empty containers until it is necessary to fill them.